Under an amphigoric and unattractive title, this subtle and innovative study casts light on the adaptation of the first generations of the Muslim Tatar proletariat of European Russia and Siberia to their new conditions of life and communal, notably religious practice in industrial plants and mines located most of the time very far from their native places. On the basis of a rich archive material, the author notably evokes the impact of the Law of June 2, 1897 on the celebration of the holydays of the Islamic calendar, and the self-organisation of Tatar Muslim workers in distinct teams within the artel’-based organisation of the mining sector. The bulk of the article is devoted to a tentative typology of the modes of designation and financing of religious personnel and religious institutions in Muslim migrant workers’ communities. Through a series of case studies, the author distinguishes three different categories: (1) the traditional one (when an imam, either local or not, was recruited on the basis of the mobilisation of yearly means from a community of believers); (2) a category constituted by the payment of a monthly tax (of one hundredth, for instance) by the members of a group of workers; (3) a mixed model made of the addition of contributions by parishioners to the payment of wages by the local administration or factory. Endeavouring not to be misled by the words of the documents that he has been using, the author also casts light on the utilisation, in the 1910s in particular, of the status of prayer houses and imams in order to conceal the existence of Tatar-language schools to the local administration.